Item of footwear

ABSTRACT

An item of footwear for increasing leg-muscle and/or lower-abdominal-/back-muscle tone comprising: a securing means for securing the item of footwear to a foot of a user; and a sole comprising at least an upper layer, for engaging a foot of a user in use or a further upper layer, and a lower layer, for engaging the ground in use, wherein the upper layer comprises two or more materials of different compressive resistances, or densities, arranged as a frontal/toe region, an arch region and a heel region, the sole is arranged such that application of a user&#39;s weight, during use, causes instability in at least one portion of the upper layer, which requires balance correction by a user.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application of co-pending U.S. patent applicationSer. No. 12/597,815 filed Aug. 2, 2010 which was a U.S. National PhaseEntry under 35 U.S.C. § 371 of, and claims priority under 35 U.S.C.Sections 119(a)-(d), 120, 363 and 365 to, International Application No.PCT/GB2008/001490, filed Apr. 28, 2008 which designated the U.S. and atleast one other country in addition to the U.S. and claimed priority toUK Patent Application No. 07080244.9 filed Apr. 27, 2007. Thespecifications of these applications are hereby expressly incorporatedby reference in their entirety to form a part of this application.

FIELD OF THE INVENTION

The present invention relates to an item of footwear for increasingleg-muscle and/or lower-abdominal-/back-muscle tone. The invention alsorelates to an item of footwear for improvement and rehabilitation ofleg-muscle tone following ankle and/or foot injuries. The inventionfurther relates to a sole, mid-sole and/or an insole for the samepurposes. Additionally, the invention relates to a method formanufacturing said item of footwear, said sole, mid-sole and/or insoleand the use of any of the above as part of an exercise regime.

BACKGROUND OF THE INVENTION

Most shoes are purchased because of their aesthetics or their comfort.Comfort shoes are designed to provide comfortable walking and standingfor a user and often include reasonable internal padding, arch supportand comfort soles. In normal use, prior art shoes provide a good stablebase for a foot of a user and this, consequently, reduces the amount ofmuscle force required for a user to stand still or walk, whilstmaintaining good balance.

However, it has surprisingly been found that, by providing a slight, butsafely-measured, instability in the footwear, the amount of difficulty auser experiences balancing whilst walking or standing is increased and,therefore, more muscle activity is required to achieve equivalent goodbalance to when using prior art shoes. In particular, muscles such astibialis anterius, tibialis posterior, rectus femoris muscles of thequadriceps and gluteus maximus have been found to work harder whilstwearing footwear having a slight instability. Further, as is well-knownin human physiology, a muscle which is made to work harder improves instrength and has quicker recovery following exercise.

SUMMARY OF THE INVENTION

Accordingly, there is a need for an item of footwear that aids muscletoning and strengthening whilst a user is standing or walking around asthey would do normally. Further, a user would not need to find specifictime for training, as training of those muscles can be provided whilstcarrying out normal activities, such as walking.

Accordingly, in a first aspect this invention provides an item offootwear for increasing leg-muscle and/or lower-abdominal-/back-muscletone comprising:

a securing means for securing the item of footwear to a foot of a user;and a sole comprising at least an upper layer, for engaging a foot of auser in use or a further upper layer, and a lower layer, for engagingthe ground in use,

wherein the upper layer comprises two or more materials of differentcompressive resistances, or densities, arranged as a frontal/toe region,an arch region and a heel region, the sole is arranged such thatapplication of a user's weight, during use, causes instability in atleast one portion of the upper layer, which requires balance correctionby a user.

Advantageously, a user of the item of footwear is caused to increasemuscular activity whilst standing and walking to keep good balance.Therefore, muscle toning and strengthening is provided whilst, merely,standing and walking around. As indicated, balance correction on thepart of the user requires additional muscle activity. When theinstability is calibrated correctly, it is barely perceivable on thepart of the wearer; however, over many steps, and when used in alifestyle approach to fitness, the additional muscle activity requiredcan help increase strength and levels of fitness in the musclegroups—especially as part of an exercise or rehabilitation regime. Mostpreferably, the item of footwear should be used frequently and as partof a daily exercise/rehabilitation regime.

According to a second aspect of the invention, there is provided an itemof footwear for increasing leg-muscle and/orlower-abdominal-/back-muscle tone comprising: a securing means forsecuring the item of footwear to a foot of a user; and

a sole comprising two or more materials of different compressiveresistances, or densities, arranged as a frontal/toe region, an archregion and a heel, the sole being arranged such that application of auser's weight, during use, causes instability in the at least oneportion of the upper-sole, which requires balance correction by a user,

wherein the sole comprises an upper surface, for receiving a foot of auser or an upper layer of sole, and a lower surface, for contacting theground or a lower layer of sole, the upper surface and the lower surfacebeing closer together at the frontal/toe region than they are at theheel region to aid comfort and provide the feel to a user of a normalitem of footwear.

According to a third aspect, the invention provides an item of footwearfor increasing leg-muscle and/or lower-abdominal-/back-muscle tonecomprising:

a securing means for securing the item of footwear to a foot of a user;and a sole comprising two or more materials of different compressiveresistances, or densities, arranged as a frontal/toe region, an archregion and a heel region, the sole being arranged such that applicationof a user's weight, during use, causes instability in the at least oneportion of the upper-sole, which requires balance correction by a user,

wherein the thickness of the sole tapers from the heel to thefrontal/toe region, to aid comfort and provide the feel to a user of anormal item of footwear.

According to a fourth aspect of the present invention, there is providedan insole for use with an item of footwear, for increasing leg-muscleand/or lower-abdominal-/back-muscle tone, the insole for receiving atleast a portion of a foot of a user in use,

the insole comprises two or more materials of different compressiveresistances, or densities, arranged as a frontal/toe region, an archregion and a heel region, the insole is arranged such that theapplication of a user's weight, during use, causes instability in theportion of the insole, which requires balance correction by a user.

According to a fifth aspect of the present invention, there is provideda method of moulding part of an insole or a sole of a shoe comprising:

providing an arch region of first material of relatively lowercompressive resistance or density;

providing a frontal/toe region and heel region of second material ofrelatively higher compressive resistance or density; and

placing the arch region between the frontal/toe region and the heelregion within a mould, and bonding the frontal/toe region, the archregion and the heel region together to form a unitary (in) sole having awobble effect which, in use, requires balance correction by a user.

According to a sixth aspect of the present invention, there is providedan exercise regime using an item of footwear, as disclosed in claims 1to 33, or an insole, as disclosed in claims 34 to 39 for increasingleg-muscle and/or lower-abdominal-/back-muscle tone, including wearingthe item of footwear or an item of footwear containing the insole andapplying weight to the item of footwear or insole to provide leg-muscletoning whilst standing and/or walking.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described, byway of example only, with reference to the accompanying drawings, inwhich:

FIG. 1 is a schematic plan view of an item of footwear according to thepresent invention;

FIG. 2 is a schematic side elevation view of the item of footwear ofFIG. 1;

FIG. 3 is a schematic side elevation view of the item of footwear ofFIG. 1 showing bonding of a frontal/toe region, an arch region and aheel; and

FIG. 4 is a schematic side elevation view of the item of footwear ofFIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an item of footwear. In particular, aflip-flop is shown in the Figures and is, generally, referenced as 1.The flip-flop 1 includes a sole 2 and a strap arrangement |3|.

As shown, the sole 2 is provided by an upper-sole 2A, a mid-sole 2B anda lower-sole 2C. The upper-sole 2A is bonded to the mid-sole 2B and themid-sole 2B is bonded to the lower-sole 2C to provide a unitary sole 2.The upper sole 2A is provided to receive a foot of a user and istextured to provide gripping surfaces between a foot of a user and theflip-flop 1. In one embodiment, the upper-sole 2A may be integral withthe mid-sole 2B (i.e. one layer) or, alternatively a separate layer. Thelower-sole 2C is provided as a plantar surface of the flip-flop 1, i.e.a surface which contacts the ground, and may be provided with one ormore ridges or grooves (not shown) for providing grip between the groundand the flip-flop 1. The lower-sole 2C is preferably one piece ofmaterial prior to bonding with the upper-sole 2A or mid-sole 2B.Naturally, as it contacts the ground, the lower-sole 2C is provided by astrong material having good wear characteristics. The sole 2 of theflip-flop 1 is provided in three general and approximate regions, as canbe seen in FIGS. 1 and 2 in particular. An approximate frontal/toeregion is indicated by reference 4. Further, an approximate arch regionis indicated by reference 5. Further still, an approximate heel regionis indicated by reference 6. In particular, the three regions of thesole 2 are provided by two or more materials of different compressiveresistances, or densities, with the arch region being provided by thematerial of least compressive resistance or density. The sole 2 isarranged such that application of a user's weight/motion, during use,causes instability in the one or more portions of the sole whichrequires balance correction by a user. The amount of instability causedis quite slight but enough for small balance corrections to be made bythe muscles of a user's leg. In particular, it is likely that the smallbalance corrections are carried out by a user sub-consciously, or withvery little thought, but, nevertheless, it would be clear, when measuredwith biomechanical monitoring equipment, that increased activity of themuscles was apparent. A firm heel region (relative to the arch region)is important because the heel needs a firm level of compressionresistance or density to give stability and propel the foot into theraid stance quickly and safely. If a heel region is too soft, the bodyresponds by forcing the heel down harder at strike in order to gainstability faster—this can have poor consequences—so a soft heel regionis preferred.

The arch region is a “question zone” where the foot is suddenly beingasked questions—it is fooled by the heel region into thinking it is on afirm surface and the instability means it needs to respond to the softerarch region—go forward, go back, adjust left and right—responding tothese questions takes effort and uses energy all the way up the leg.

The firmer toe region maintains speed of walking and gives the foot thestability and direction it needs to propel in the right direction—a softtoe region means using more than the big toe to step off and that isalso not preferred.

The footbed profile is designed to not support the arch—rather allow thefoot to behave naturally—it is not telling the foot what to do or how tobehave.

In this particular embodiment, the sole 2 according to the presentinvention is provided by a specially constructed, multi-density materiallayer. In particular, the sole 2 is provided with the arch region 5being of a first material of relatively lower compressive resistance ordensity, and a frontal/toe region 4 being of a second material ofrelatively higher compressive resistance or density. Further, the heelregion 6 is provided by a third material—different from the secondmaterial—of relatively higher compressive resistance or density, whencompared to the arch region 5. In particular, this embodiment describesa sole 2 having a harder heel region 6, a softer arch region 5 and aharder frontal/toe region 4, relative to each other. In a preferredembodiment, the frontal/toe region 4 is slightly softer than the heelregion 6 but both the heel region 6 and the frontal/toe region 4 areharder than the arch region 5. By way of example, the hardness of theparts of the mid-sole 2B can compared using the Asker C scale testmethod (SATRA TM205:1999, with 15 second reading being taken) and theheel region 6 is preferably 54 (harder), the arch region 5 is 31(softer) and the frontal/toe region 4 is 45 (also harder but not as hardas the heel 6). It is desirable to make the heel region 6 and thefrontal/toe region 4 harder as the heel takes the most impact and inaddition facilitates the forward motion of the foot when walking whilethe toe need to provide good ‘push off’ for walking.

As can be seen in FIG. 3, the frontal/toe region 4 abuts the arch region5 along an interface 7. At the interface 7, the material of thefrontal/toe region 4 is bonded to the material of the arch region 5. Ina similar way, an interface between the arch region 5 and the heel 6 isprovided at the interface 8. Although the interface 7,8 between thematerial could be vertical in nature, i.e. in the direction of thelower-sole 2C towards the upper-sole 2A, it is preferred to have a|tapered| interface that allows an overlap of materials from either sideof the interface 7, 8. In particular, a tapered portion 4A of thefrontal/toe region 4 overlaps with a tapered portion 5A of the archregion 5 in a horizontal overlap to form the interface 7. Further, atapered portion 5B of the arch region 5 and a tapered portion 6A of theheel 6 overlap in a horizontal manner to form the interface 8.Advantageously, the tapered interfaces 7,8 provide a seamless joinbetween the parts of the mid-sole 2B and provide a smoother transitionfrom the harder 6,4 to softer 5 areas of the mid-sole 2B. Alternatively,the tapered portions 4A, 5A, 5B, 6A could be considered to bewedge-like.

FIG. 4 shows a most preferred embodiment of an item of footwear. As canbe seen from that figure, the joining parts 4A1, 5A′, 5B′ and 6A1 of thefrontal/toe region 4, arch region 5 and heel region 6 haveirregularly-shaped joining edges. This increases the surface area of thebond between those regions. Whilst the irregularly-shaped edges may beprovided on the regions prior to heating in the mould, it is also abeneficial consequence of the method of manufacture that they areprovided in the formed item of footwear. Of course, the same applies toan insole of the present invention.

Advantageously, as can be seen in the Figures, the sole 2 isanatomically-shaped. The materials of the frontal/toe region 4, the archregion 5 and the heel 6 are arranged to provide a wobble effect—slightinstability—such that the foot, when stepping across the sole from heel6 to toe 4 wobbles slightly, altering the balance position of a user'sfoot. The wobble effect can be medio-lateral or anterior-posterior or acombination of anterior-posterior and medio-lateral instability. Inparticular, it is the progression from the heel 6 and the arch region 5,and the progression from the arch region 5 and the frontal/toe region 4that allows the mid-sole to wobble and cause slight instability.

The embodiment of sole 2 shown in the Figures is substantially made ofethylene vinyl acetate (EVA). According to the invention, threedifferent grades of EVA are utilised—having different compressiveresistances or densities—for the mid-sole to provide the wobble effect.However, it will be understood that other materials will provide anequivalent effect and examples of those materials are other elastomers,silicones, natural or synthetic rubbers and/or polyurethanes.

The strap arrangement 3 (securing means) is connected to a part of thesole 2, in the region of the heel 6 in two places, one on each side ofthe flip-flop 1. The strap arrangement 3 is also connected to theupper-sole 2A (or the mid-sole 2B) in the region of the frontal/toeregion 4 where it is positioned to be locatable between a first andsecond toe of a user.

In use, a user simply wears the flip flop 1 whilst standing or walkingaround to exercise or rehabilitate the muscles of the leg.

The method of manufacture of a sole or an insole—in particular amid-sole—according to the present invention involves using threedifferent densities of EVA material and then thermoforming them in asingle mould to form a unitary (in) sole 2B. In particular, the materialis combined using three different densities of uncured solid EVAcompounds that have been pre-cut to approximate shape (heel, arch, toe)and introducing them to a first stage mould. The mould is heated to 160degrees for β minutes in which time the solid compounds (EVA) melt,combine—although they remain roughly in the area of the mould they wereintroduced to—and release gases which are unable to escape. After briefcooling the mould is quickly released and the emerging mid-sole 2Bexperiences a sudden and dramatic increase to around four times the sizeof the mould it emerged from. This forms an EVA ‘caster’ unit. This EVA‘caster’ unit is still at a lower density (and a rough shape) andrequires further heating to reach the required density and take thefinal anatomical shape, by way of example, shown in the Figures, andthis is done by trimming the ‘caster’ and placing it in a second stagemould, where it is subjected to heating for a further 6 minutes andcooling for a further 6 minutes to take the shape of the final product.Additionally, a lower-sole 2C can be subsequently added to the mid-sole2B. Alternatively, the lower-sole 2C can be bonded with the mid-sole 2Bin either or both moulds. The upper-sole 2A may be subsequently bonded,and may comprise a fabric layer.

In relation to an insole for use with an item of footwear, it will beunderstood that the insole can be placed in an item of footwear as anadditional or alternative insole to that supplied with the footwear, ormay be made integral with the item of footwear. Further, from thecontext of the claims, it will be understood that the insole may haveany number of the sole features claimed in relation to the item offootwear. Accordingly, as the sole features of the item of footwear andthe features of the insole are substantially identical, if notidentical, reference is drawn to the corresponding passages.

While the invention has been described with reference to a preferredembodiment, it should be understood by those skilled in the art thatvarious changes may be made and equivalents substituted for elementsthereof without departing from the scope of the invention. In addition,many modifications may be made to adapt a particular situation ormaterial to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

We claim:
 1. A method of molding a part of an insole or a sole of ashoe, comprising: providing an arch region of first material ofrelatively lower compressive resistance or density; providing afrontal/toe region and heel region of second material of relativelyhigher compressive resistance or density; placing the arch regionbetween the frontal/toe region and the heel region within a mold; andbonding the frontal/toe region, the arch region and the heel regiontogether to form a unitary insole or sole having a wobble effect which,in use, requires balance correction by a user, wherein at least aportion of a lower-facing surface of each of the arch region, thefrontal/toe region and the heel region are substantially planar with oneanother without a force being exerted on the unitary insole or sole bythe user.
 2. The method as claimed in claim 1, wherein bonding thefrontal/toe region, the arch region and the heel region togetherincludes heating the materials.
 3. The method as claimed in claim 2,wherein bonding the frontal/toe region, the arch region and the heelregion together includes compression of the materials.
 4. The method asclaimed in claim 2, wherein the mold includes a waffle press-typebonding apparatus.
 5. The method as claimed in claim 1, wherein themethod includes a first-stage molding process to provide a caster unitand a second-stage molding process to provide the unitary insole orsole.
 6. The method as claimed in claim 1, wherein an additional layeris bonded to either or both of an upper-facing layer or a lower-facinglayer of the unitary insole or sole.
 7. The method as claimed in claim1, wherein providing the arch region and providing the frontal/toeregion and the heel region further include providing joining edges ofthe frontal/toe region and the arch region, and/or the arch region andthe heel region that are irregularly-shaped, or correspondingly-tapered,to provide an increased sealing surface area.
 8. The method as claimedin claim 3, wherein the method includes a first-stage molding process toprovide a caster unit and a second-stage molding process to provide theunitary insole or sole.
 9. The method as claimed in claim 3, wherein anadditional layer is bonded to either or both of an upper-facing layer ora lower-facing layer of the unitary insole or sole.
 10. The method asclaimed in claim 3, wherein providing the arch region and providing thefrontal/toe region and the heel region further include providing joiningedges of the frontal/toe region and the arch region, and/or the archregion and the heel region that are irregularly-shaped, orcorrespondingly-tapered, to provide an increased sealing surface area.11. The method as claimed in claim 8, wherein providing the arch regionand providing the frontal/toe region and the heel region further includeproviding joining edges of the frontal/toe region and the arch region,and/or the arch region and the heel region that are irregularly-shaped,or correspondingly-tapered, to provide an increased sealing surfacearea.
 12. The method as claimed in claim 9, wherein providing the archregion and providing the frontal/toe region and the heel region furtherinclude providing joining edges of the frontal/toe region and the archregion, and/or the arch region and the heel region that areirregularly-shaped, or correspondingly-tapered, to provide an increasedsealing surface area.
 13. The method as claimed in claim 1, wherein thewobble effect is in a medio-laterial direction.
 14. The method asclaimed in claim 13, wherein the wobble effect is in ananterior-posterior direction.
 15. The method as claimed in claim 1,wherein the wobble effect is in an anterior-posterior direction.